Pre-emergent bioherbicidal potential of microwave/ultrasound-extracted creosote bush and tarbush on buffalo gourd

Abstract

Effective, safe weed control is crucial for sustainable food production. Bioherbicides derived from plant extracts present a promising alternative. Extracts from plants like creosote bush (Larrea tridentata) and tarbush (Flourensia cernua) contain allelopathic compounds that can disrupt weed germination and growth. The aim of this study was to evaluate the effect of L. tridentata and F. cernua extracts on pre-emergent control of buffalo gourd (Cucurbita foetidissima). Plant extracts were prepared using microwave and ultrasound technologies with "green" solvents and were applied at different doses [3 (low), 6 (medium), and 12 (high) L of extracts in 200 L per hectare] on C. foetidissima seeds, and their effect on germination, seedling growth, dry biomass, and mechanisms of action [on photosynthetic pigments (chlorophylls a, b, total, and carotenoids), total proteins, antioxidant enzymes (catalase and peroxidase), total phenolic compounds, antioxidant capacity, and oxidative stress (lipid peroxidation)] were evaluated. The phytochemicals like quercetin and (+)-gallocatechin in the bioherbicide extract were found. The high dose of the extract decreased germination rates and decreased seedling growth in C. foetidissima compared to the control. Although dry biomass showed no significant change, a trend toward reduction was observed in treated seedlings. Chlorophyll and carotenoid levels decreased in all treatments, while protein levels were unaffected. Low-dose treatments decreased catalase activity, and the high dose increased lipid peroxidation. This study demonstrates that allelopathic plant extracts effectively inhibit C. foetidissima seedling growth, with compound concentration and content critical to bioherbicide effectiveness